Liquefiable material packaged in flexible plastic containers

ABSTRACT

A NORMALLY SOLID OR SEMI-SOLID MATERIAL, SUCH AS ASPHALT, PARAFFIN WAX, SULFUR, ETC., IS PACKAGED IN PLASTIC BAGS BY FEEDING THE MATERIAL IN A MOLTEN STATE TO A PLASTIC TUBE SEALED AT ITS BOTTOM END AND DISPOSED WITHIN A MOLD WHICH SERVES TO SUPPORT, COOL AND SHAPE THE PLASTIC TUBE DURING FILLING. AFTER FILLING TO A DESIRED LEVEL, THE TUBE CONTAINED WITHIN THE MOLD IS SEALED AT A POSITION ABOVE THE LEVEL OF THE MATERIAL, SEVERED THEREAT FROM THE UNFILLED PORTION OF THE PLASTIC TUBE AND THEREAFTER RELEASED   FROM THE MOLD AND FURTHER COOLED TO PROVIDE A FLEXIBLE CONTAINER HOLDING A SOLIDIFIED MATERIAL.

Feb 23, 1971 G. E. KENT LIQUEFIABLE MATERIAL PACKAGED IN FLEXIBLEPLASTIC CONTAINERS Filed Nov. 8, 1968 MOLTEN ASPivllALT 5. Km InventorUnited States Patent O U.S. Cl. 53-25 14 Claims ABSTRACT OF THEDISCLOSURE A normally solid or semi-solid material, such as asphalt,paraffin wax, sulfur, etc., is packaged in plastic bags by feeding thematerial in a molten state to a plastic tube sealed at its bottom endand disposed within a mold which serves to support, cool and shape theplastic tube during filling. After filling to a desired level, the tubecontained within the mold is sealed at a position above the level of thematerial, severed thereat from the unfilled portion of the plastic tubeand thereafter released from the mold and further cooled to provide aflexible container holding a solidified material.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to a method and apparatus for the packaging of fusible material.More particularly, the invention is concerned with the packaging of afusible material such as asphalt, wax, sulfur, etc., in flexible,thin-walled plastic bags.

Description of the prior art Asphalt and similar materials which can bepoured when hot and which solidify on cooling are conventionallypackaged in wooden, metallic or other non-flexible containers.Ordinarily, the material to be packaged is fused and the molten materialis poured into the container which, if necessary, is then immediatelysealed. Rigid containers do not require external support during fillingand can be easily transported while the material is still in the moltenstate.

The use of wooden and metal drums or similar rigid containers has,however, the drawback that the material contained therein can only beremoved with difficulty since the material adheres to the inner wall ofthe containers. In order to obviate the drawback, it is already known toprovide containers prepared from strong cardboard with an inner liningconsisting of a metal foil and a film of cellulose acetate, the metalfoil being glued to the inner side of the container, and the celluloseacetate film to the metal foil. The molten material, e.g., bitumen,which is poured into these containers when hot adheres to the celluloseacetate film while solidifying, so that in order to remove the packagingthe cardboard with the metal foil must be stripped from the celluloseacetate film.

The containers provided with an inner lining are both inconvenient andexpensive to use. British Pat. No. 935,- 357 attempts to overcome thedeficiencies associated with the prior packaging methods by providing anasphalt bagging technique wherein molten asphalt is poured into aflexible plastic container while the container is progressively immersedin a water bath. After filling, the plastic Patented Feb. 23, 1971container is sealed and allowed to remain in the water bath until theasphalt has solidified. Unfortunately, this prior art technique has thedisadvantage that some facility must be employed to allow for gradualsubmersion in the Water bath, e.g., the use of a counter weight systemwhich would limit production.

SUMMARY OF THE INVENTION In accordance with the invention, material tobe packaged is liquefied by heating and fed in a molten state to aflexible plastic container positioned in a rigid mold ex posed tocooling means. In a preferred embodiment, there is provided a processfor packaging normally solid or semi-solid material which comprisesliquifying said material by heating; downwardly advancing a continuous,flexible plastic tube into a mold forming a support and heat transfersurface therefor, said plastic tube being closed at its bottom end;feeding a predetermined amount of said liquefied material to the plastictube disposed within the mold; cooling the mold to initiatesolidification of said liquefied material and to prevent rupture of theplastic tube; closing and sealing said plastic tube at a position abovethe level of the material to form a package of material within the mold;severing the filled sealed bag from the continuous plastic tube; sealingthe bottom edge of said continuous plastic tube; releasing the filledpackage from the mold; and repeating the above steps.

The invention is applicable to the packaging of normally solid, orsemi-solid materials that are capable of being rendered fluid by heatingsuch as, for example, asphalt, paraflin wax, plastics, sulfur, etc. Theinvention is particularly applicable to the packaging of cold-settingliquids, such as asphalts, having mechanical characteristics thatprevent handling and packing of the package at normal storagetemperature Without considerable deformation.

The packaging material used herein should be sub stantially imperviousto the water or other cooling liquid employed and should not melt at thetemperature at which the molten material is packaged. Preferably, thepackaging material is one that may be incorporated in use with thematerial to be packaged without detriment thereto so that the completepackage may be used without removal of its contents. In general,suitable materials are plastics, such as polyethylene, polypropylene,polyvinyl chloride, polystyrene, cellophane and the like. When asphaltis packaged, the preferred packaging material is polyethylene.

The flexible plastic containers may be in the form of bags which may besuitably manufactured from tubular plastic foils by dividing the latterinto short sections and sealing these sections at one end by Welding orclamping means. The bags may be suspended by suitable devices belowfilling connections for supplying the material to be packaged. Thetubular foils or flexible plastic tubes may be formed in various ways.For example, plastics may be fed from rolls and welded together at theiredges. Alternately, a single sheet may be used and its two edges weldedtogether. Instead of welding strips of plastics to form the tubularfoil, plastic material may be formed into a tubular shape by directextrusion blowing. In this case, the molten material injection line canpass through the center of the extrusion profile and injection can beperformed at a distance from the extru sion outlet where the mechanicalcharacteristics of the tubular foil are sufficient for filling in themold.

It is convenient to supply materials by pumping and thus, in general,the most suitable materials for packaging according to the method of theinvention are those with a softening point above, for example, about 50C. Any filling temperature which will not cause melting of the flexiblecontainer under the conditions of filling may be used, but, in order tolimit the cooling period in the mold, it is desirable to keep thetemperature as low as possible.

BRIEF DESCRIPTION OF THE DRAWING The invention is illustrated by theaccompanying drawing showing a diagrammatic view of an asphalt baggingoperation.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now more particularly tothe drawing, molten asphalt which may be at a temperature, for example,of 225 F. is pumped through feed line 1 provided with quick closingvalve 2 which operates in an open or closed position and which isactuated by air from line 3. When valve 2 is in an open position, moltenasphalt passes through line 4 and then into plastic tube 5 which issealed at its bottom end and positioned within mold 9, having trap doorand aperture 11. Plastic tube 5 is conventionally formed (not shown)from plastic film (e.g., polyethylene of 6 mil thickness) and is cooledat a position above mold 9 by means of water spray 6 which is suppliedwith water via line 7. Mold 9 is cooled by means of water supplied vialine 12 to spray 13 which, when polyethylene is used as the packagingmaterial, maintains mold 9 at a temperature within the range betweenabout 60 and 150 F., e.g., 100 F. The mold may have movable sides whichcan be adjusted to form a bag of desired shape. Thus, mold 9 not onlysupports and cools the bag during filling but also shapes the filledcontainer.

During the filling operation, air passes through line 14 into line 15and then through aperture 11. When the asphalt being supplied to plastictube 5 reaches the level of aperture 11, the passage of air therethroughis blocked by tube 5 so that the supply of air from line 14 is directedinto lines 16 and 3 to thereby close valve 2 and into line 17 to therebyactuate control-timer 18 which signals means 8 to seal and cut plastictube 5 at a position above the level of the asphalt after the closing ofvalve 2. When the delivery of the asphalt ceases, the walls of plastictube 5 are brought together, heat-sealed and cut by means 8 therebypackaging the asphalt within a thin plastic film. The filled bag is thenpermitted to drop through trap door 10 (shown open) into water filledtrough 19 where additional heat is removed by water bath 20 prior tohandling and storing of the filled packages 21.

It will be understood that changes in detail may be resorted to withoutdeparting from the field and scope of the invention, and it is notintended to limit the invention to the exact details of structure andoperation herein shown and described, as various modifications withinthe scope of the appended claims may occur to persons skilled in theart.

What is claimed is:

1. A process for packaging a liquefiable normally solid or semi-solidmaterial on a continuous basis which includes the following steps:

(a) downwardly advancing a continuous plastic tube into a rigid moldhaving a wall closely conforming the wall of said tube, said tube beingclosed at its lower end to form a bag prior to entry into said mold;

(b) spraying a liquid cooling medium on the exterior wall of said mold;

(c) feeding a predetermined quantity of said material in liquefied forminto said bag positioned within said mold;

(d) sealing said plastic tube above said material after saidpredetermined quantity thereof has entered said bag, thereby forming afilled closed container;

(e) severing said closed container from the continuous plastic tubeabove it;

(f) sealing the bottom of the severed plastic tube above the closedcontainer, thereby forming a new bag;

(g) removing the severed closed container through the bottom of saidmold;

(h) repeating steps (a) through (g).

2. The process of claim 1 including the step of cooling the plastic tubeprior to its entry into the mold.

3. The process of claim 1 including the step of exposing the filled bagcontainer removed from the mold to a bath of cooling fluid.

4. The process of claim 1 wherein said material is asphalt.

5. The process of claim 1 wherein said plastic is polyethylene.

6. The process of claim 1 which includes the step of conducting a streamof gas through an opening in an upper portion of the wall of the moldinto the annulus between the wall of the tube and the wall of the mold,whereby completion of the filling of said bag can be signaled by achange in gas flow resulting from the closing of said annulus adjacentsaid wall opening.

7. The process of claim 6 which includes the step of utilizing saidchange in gas flow to actuate means for cutting off flow of liquefiedmaterial into said bag.

8. The process of claim 6 which includes the step of utilizing said gasflow change to actuate means for performing said sealing and severingsteps.

9. An apparatus for packaging a liquefiable normally solid or semi-Solidmaterial in plastic film on a continuous basis which comprises, incombination:

(a) a support mold having a vertical side Wall, an

open top, and a supporting bottom movable between a closed position andan open position;

(b) means for downwardly advancing a continuous tube of plastic filminto said mold in closely conforming relation with the side wall of saidmold;

(0) means for introducing liquefied material within the portion of saidtube positioned within said mold;

(d) means for spraying a cooling liquid on the exterior wall of saidmold;

(e) means for sealing said tube in a region above material introducedinto said tube within the said mold;

(f) means for severing said sealed portion of the tube from thecontinuous tube above it to thereby form a sealed package of material;

(g) means for sealing the bottom edge of the remaining continuous tube;

(h) means for moving said supporting bottom to the open position wherebyto remove said sealed package.

10. An apparatus as defined by claim 9 including means for sprayingcooling liquid on the exterior of said tube of plastic film above saidmold.

11. An apparatus as defined by claim 9 including means for introducing astream of gas through an upper portion of a vertical wall of the mold.

12. An apparatus as defined by claim 11 including means for detectingwhen the flow of said stream of gas into said mold has changed as aresult of closing of the annulus between said wall and said tube ofplastic film.

13. An apparatus as defined by claim 12 including means, associated withsaid detecting means, for actuating said severing means and said sealingmeans.

14. An apparatus as defined by claim 9 including means for introducing astream of gas through an upper portion of a vertical wall of said moldinto the annulus between said wall and the plastic tube positioned insaid molds, and means, actuated by change in gas flow into said annulus,for cutting off fiow of liquefied material into said plastic tube,whereby the closing of said annulus by the filling of the tube withliquefied material to a predetermined level within the mold willautomatically regulate the quantity of material fed into the package.

References Cited UNITED STATES PATENTS Grove 5325 Kraft 5323X Breeze53-21X Birdseye 5327X Potts 5325 Gillican 5325 Gillican 5325 Wacker53-24X Jones 53-24X Singer 5321FC Burrell 5323X Arcudi 5325 Churchill53--23 Berckmoes 5325 Rausing 5327 US. Cl. X.R.

